In a conventional image input apparatus, upon receiving user input for, e.g., controlling the image sensing direction of the image input apparatus from user input means such as a panel, remote controller, camera switch, or the like, that input is converted into a request inside a system, and the request is processed to implement a given function.
There are two modes, i.e., a local control mode and host control mode which differ from each other in method of processing a request.
In the local control mode for accepting user input only from the image input apparatus, all requests are interpreted by a request interpreter inside the apparatus, and processes are executed according to the interpretation results.
In the host control mode for accepting user input from both of the image input apparatus and the host computer, all requests by a user from user input means such as a panel, remote controller, camera switch, and the like are sent to a host computer connected without being interpreted inside the apparatus, and processes are executed upon receiving corresponding commands from the host computer.
FIG. 8 is a block diagram for explaining the process of the conventional image input apparatus in the local control mode, FIG. 9 is a block diagram for explaining the process of the conventional image input apparatus in the host control mode, FIG. 10 is a flow chart for explaining the operation of a user input process in the conventional image input apparatus, and FIG. 11 is a flow chart for explaining the operation of the conventional image input apparatus upon receiving a command from the host computer.
Since the local control mode is selected upon starting up the apparatus, a control mode determination unit 205 determines the local control mode. The operation at that time will be explained below with reference to FIGS. 8 and 10.
Upon receiving user input at a remote controller receiver 202 in step S201, a user input converter 204 generates a request corresponding to the user input in step S202. The request is sent to the control mode determination unit 205. Since the apparatus has initially been started up in the local control mode (NO in step S203), the request is sent to a request interpreter 206. In step S204, the request interpreter 206 converts the request into an internal command, and sends it to an internal command execution unit 207. In step S205, the internal command execution unit 207 executes the process. After the control mode is switched to the host control mode in a sequence to be described later, the request generated in step S202 is sent to the host computer in step S206 without being executed inside the apparatus.
Switching control from the local control mode to the host control mode, switching control from the host control mode to the local control mode, and control in the host control mode will be explained below.
Switching control to the host control mode will be described first with reference to FIGS. 8 and 11. Upon receiving a command from the host computer via a host interface 210 and command receiver 209 in step S210, the received command is sent to a command interpreter 211 and is converted into an internal command in step S211. The command interpreter 211 checks if the received command is a host control mode switch command. If the received command is the host control mode switch command (YES in step S212), the command interpreter 211 generates a corresponding internal command, and sends it to the internal command execution unit 207. The internal command execution unit 207 instructs the control mode determination unit 205 to switch the control mode to the host control mode, and the control mode determination unit 205 switches the control mode to the host control mode in step S213, thus ending the processing. Upon switching to the host control mode, a link state is changed to that shown in FIG. 9.
Switching control to the local control mode will be explained below with reference to FIGS. 9 and 11. If it is determined in step S212 that the command received in step S210 is not a host control mode switch command, the flow advances to step S214 to check if the received command is a local control mode switch command. If the received command is the local control mode switch command, the flow advances to step S215, and an internal command generated by the command interpreter 211 in step S211 is sent to the internal command execution unit 207. The internal command execution unit 207 instructs the control mode determination unit 205 to switch the control mode to the local control mode, and the control mode determination unit 205 switches the control mode to the local control mode, thus ending the processing. After that, upon receiving user input in step S201 in FIG. 10, the processes in steps S204 and S205 mentioned above are executed.
If it is determined in step S214 in FIG. 11 that the received command is not a local control mode switch command, the control mode determination unit 205 checks in step S216 if the current control mode is the host control mode. If NO in step S216, the received command is ignored, and the processing ends. On the other hand, if YES in step S216, the flow advances to step S217, and an internal command generated by the command interpreter 211 in step S211 is sent to the internal command execution unit 207. Then, the internal command execution unit 207 executes a process, thus ending the processing.
However, in the aforementioned system, since all requests, inputted to the image input apparatus, including those which need not be sent to the host computer are sent to the host computer in the host control mode, the processing on the host computer side unwantedly becomes complicated.
In the host control mode, since all user inputs are processed in the sequence of:
(1) a request is sent to the host;
(2) the host computer interprets the request;
(3) the host computer sends a command; and
(4) the command is received to execute a process, a large time lag is generated from each user input to execution of the process.